Numerical simulation of three-dimensional rock fragmentation by disc cutters of tunnel boring machine using peridynamics

Peridynamics is a non-local mesh-free numerical method which has great advantages in simulating dynamic damage and fracture. This work proposes to use the peridynamics to simulate rock fragmentation by TBM disc cutters and seven tests are simulated to verify this idea. The feasibility of peridynamics in simulating rock fragmentation by TBM disc cutters is demonstrated by comparisons with the punch indentation tests. A nonlinear short-range force contact model is proposed to better reflect the variation of the disc cutter normal force with respect to indentation depth, and can also calculate the changing contact area between the disc cutter and the rock during the indentation. In addition, the proposed non-linear short-range force contact model is used to simulate five 3D TBM disc cutter indentation tests with different bi-directional confining stress conditions, and the numerical results are compared with the experimental results. The simulation results show that the proposed contact model is able to calculate the variation of the cutter peak force with different confining stress and to obtain a reasonable form of rock surface damage. Peridynamics approach is easy to operate and requires only two calibration parameters to simulate the 3D rock fragmentation by disc cutters, which is promising for practical engineering applications.